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Aluminum is incredible stuff. If it wasn't so common, its combination of desirable properties, great strength, lightness, corrosion resistance, and easy workability, would make it seem incredibly useful. People would say, man, if only we could get more aluminum, we could make all kinds of things out of it! In fact, that's exactly what happened: When it was first isolated the only process for getting it was extremely difficult, and as a result it was rare and expensive. Napoleon had dinnerware made out the amazing new precious metal. But people knew it was common in many rocks and minerals, and before too long a quick, cheap process using electricity was discovered for refining large quantities inexpensively.
Today aluminum refining is one the largest users of electricity in the world. So much electricity is required that aluminum refining is done not near where the aluminum ore is, but near where the power is (for example near large hydroelectric plants that can supply cheap power).
Although aluminum is still more expensive than iron/steel, it is often used in place of cast iron because it is much easier to cast, and because the resulting pieces are much easier to lift. Although you might say that cast aluminum benches, lamp posts, etc, are "imitation", it's hard to think of a single way in which they are not superior to the iron originals. They are stronger (weight-for-weight anyway), they don't rust, they are much easier to install and move, you can paint them and expect the paint to last, and so on.
Rockets and large airplanes would basically be impossible without aluminum: No other material that is inexpensive enough to even consider using is light and strong enough to make a large jetliner work. (Some day carbon fiber composites and the like may take over this role, but at this point they are still way too expensive.)
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 4/0 electrical wires.
This was from heavy-gauge electrical wire left over from when we added the round house at the farm. It's been melted down and allowed to cool in the standard graphite crucible used for many metal samples. It came out very ugly, so I used a grinder, table top belt sander, and wire brush in the drill press to machine it into a cleaner cylinder with a pleasing texture on the surface. I got the wire from a building center in the mid 1990s.
Aluminum wiring is used today only for large-diameter service entrance cable, because it's difficult and often dangerous when used for individual branch circuits, as it was for a time during the 1970's. This link provides more information about aluminum wiring.
Source: Hardware Store
Contributor: Theodore Gray
Acquired: 15 April, 2002
Price: $1/foot
Size: 1.25"
Purity: >95%
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 Water drop blobs.
This globular stuff is what happens if you pour molten aluminum into a deep bucket of water. You can pour any kind of molten metal into water and each kind will give you different shapes. The shapes depend on how high you pour from, how much above its melting point the metal is, and how deep the water is. According to certain traditions, the shapes also depend on your fate, hence can be used to predict it (most traditions specify lead, but I don't see any reason why aluminum would be less likely to work for this purpose).
Any time you combine water with molten metal, there is a danger of the metal splattering. Generally speaking, if you pour metal into a reasonably full bucket of water, it sinks and cools too fast for any to splatter back at you (which is not to say it can't happen, so use a face shield). But if you pour (or even drip) water into a container of molten metal, it's a different story: That is quite likely to cause a steam explosion that throws liquid metal all over. So when you're pouring metal into water, the biggest danger is if any water happens to splash back into the bowl you're pouring out of. Pour away from you, so the bowl is between you and the metal, don't lean over it while you're pouring, and wear thick clothes and sturdy shoes along with a face shield or at least glasses. (I should talk: I made these lumps barefoot in shorts and no shirt. It's OK because I'm a trained professional idiot. And no matter what other precautions I don't take, I would never do this without glasses on. I can risk missing a few square inches of skin, but not missing an eye.)
These were made from the same wire as the sample above.
Source: Hardware Store
Contributor: Theodore Gray
Acquired: 15 April, 2002
Price: $1/foot
Size: 1.25"
Purity: >95%
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 Gem cut aluminum oxide (corundum).
These are real rubies and sapphires purchased from http://www.pehnec.com in April 2002. Real because they are chemically and crystallographically indistinguishable from naturally occurring gems (that would cost well into 5 figures). Present in the table because they are man-made (real, but synthetic).
Source: Pehnec Gems
Contributor: Theodore Gray
Acquired: 23 April, 2002
Price: $15/both
Size: 0.6"
Purity: 53%
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Artificial knee joint (practice version).
After starting to collect elements I researched industrial uses of pure elements in search of products I might be able to get as samples. For titanium and tantalum a promising source seemed to be artificial body parts, since these are the only two elements used for that purpose, because they are unreactive with human body fluids. I joked to my long suffering colleagues that all I needed to do was find the right body to dig up. I think they were worried.
And of course not two days later I found an eBay listing for a human tibia with attached artificial knee joint. (There is nothing you can't buy on eBay, though I'm told it's actually a femur so be sure to double check any human remains auctions before bidding.) The dealer seemed to be a legitimate outfit in Berkeley, California, and they indicated they thought it was probably titanium. I secretly hoped it was tantalum, which would have made it worth a serious amount of money.
I won the auction for $31, which seems like a very fair price for half of someone's leg. (This would, by the way, set the price for an arm and a leg at approximately $120, a real bargain.) But doubt remained as to the true identity of the metal. According to the seller, this item had been made by the manufacturer of the artificial knee for use in training surgeons in the use of that company's special drills and tools. I hope they learned well, because it's got several cuts on it where it looks like someone slipped....
Since it was never meant to be implanted into a living person, I was worried they might have saved some money by using a cheaper alloy. I was right to worry. Through the good graces of Inga Karliner of the University of Illinois physics department I was put in contact with Ivan Petrov of the U of I's materials research department, which just happens to be a national collaborative center for materials testing, which means they have a hallway with something like two dozen very fancy instruments for telling me what my knee joint is made of.
Dr. Petrov's colleague Jim Mabon confirmed my fears with a quantitative analysis by x-ray fluorescence spectroscopy:
99.78% Aluminum
0.109% Iron
0.0062% Nickel
0.0053% Copper
0.0257% Zinc
In other words, common aluminum casting alloy. (Not only that, reader Don Keck tells me it's probably a femur, not a tibia, so the eBay description wasn't even right in that regard.) Interestingly, there was a 0.074% trace of titanium, which makes me think it was probably cast in the same mould, or maybe the aluminum was melted in the same crucible, as the titanium parts used on living people. There was not so much as the slightest detectable trace of tantalum. (Per the terms of their service, I should mention that this analysis was carried out in the Center for Microanalysis of Materials, University of Illinois, which is partially supported by the U.S. Department of Energy under grant DEFG02-91-ER45439.)
Oh well, by then I'd become attached to my little bone, and it will have a place of honor under aluminum. After all, this was someone's leg, maybe someone's daddy's leg, and it deserves respect. (It is claimed to be a pre-1987 leg from India.)
Source: The Bone Room
Contributor: Theodore Gray
Acquired: 13 May, 2002
Price: $31
Size: 4"
Purity: 99.78%
Sample Group: Body Parts+Medical
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So-called "Titanium" racket.
"Racket" may be the right word for this sample, which used to be a racquetball racket prominently labeled as "TITANIUM". If it were titanium, it wouldn't have melted at about 700C in my crucible of truth.
It gets worse. It could have been one of many commonly used high-strength aluminum-titanium alloys, which contain a few percent of titanium: That would almost justify the use of the name "titanium" in the description. But analysis by x-ray fluorescence spectroscopy at the Center for Microanalysis of Materials, University of Illinois (partially supported by the U.S. Department of Energy under grant DEFG02-91-ER45439) indicates the following composition:
98.44% Aluminum
0.55% Manganese
0.53% Copper
0.24% Iron
0.16% Zinc
Where's the titanium you ask? It's not there, not even the tiniest trace.
Source: Chris Carlson
Contributor: Chris Carlson
Acquired: 10 June, 2002
Price: Donated
Size: 1.25"
Purity: >95%
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Fine powder, 99.999%.
Kindly donated by David Franco, who sent many elements after seeing the slashdot discussion, and this one after I sent him some Mathematica t-shirts.
Source: David Franco
Contributor: David Franco
Acquired: 11 June, 2002
Price: Donated
Size: 0.2"
Purity: 99.999%
Sample Group: Powders
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Tiny cylinder.
Ed bought half a dozen different tiny metal cylinders from David Franco, intending to make some kind of puzzle out of them (Ed's a puzzle person). But they turned out to be too irregular, so he donated them to the table.
Source: David Franco
Contributor: Ed Pegg Jr
Acquired: 19 August, 2002
Price: Donated
Size: 0.2"
Purity: 99.99%
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Japanese coin.
I know I brought back a handful of these last time I was in Japan, but I can't find any of them. Fortunately Ed had some, and it's not like they're actually worth anything, which is why they are made of aluminum in the first place. Reader Lawrence Spiwak told me an interesting fact: A one yen coin is exactly one cm in diameter,and weighs exactly one gram. I've verified this to 5 decimal places with my analytic balance, so I know its true.
Source: Japan
Contributor: Ed Pegg Jr
Acquired: 6 September, 2002
Price: Donated
Size: 0.5"
Purity: >90%
Sample Group: Coins
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Sample from the RGB Set.
The Red Green and Blue company in England sells a very nice element collection in several versions. Max Whitby, the director of the company, very kindly donated a complete set to the periodic table table.
To learn more about the set you can visit my page about element collecting for a general description or the company's website which includes many photographs and pricing details. I have two photographs of each sample from the set: One taken by me and one from the company. You can see photographs of all the samples displayed in a periodic table format: my pictures or their pictures. Or you can see both side-by-side with bigger pictures in numerical order.
The picture on the left was taken by me. Here is the company's version (there is some variation between sets, so the pictures sometimes show different variations of the samples):
Source: Max Whitby of RGB
Contributor: Max Whitby of RGB
Acquired: 25 January, 2003
Price: Donated
Size: 0.2"
Purity: 99.9%
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Sample from the Everest Set.
Up until the early 1990's a company in Russia sold a periodic table collection with element samples. At some point their American distributor sold off the remaining stock to a man who is now selling them on eBay. The samples (except gasses) weigh about 0.25 grams each, and the whole set comes in a very nice wooden box with a printed periodic table in the lid.
To learn more about the set you can visit my page about element collecting for a general description and information about how to buy one, or you can see photographs of all the samples from the set displayed on my website in a periodic table layout or with bigger pictures in numerical order.
Source: Rob Accurso
Contributor: Rob Accurso
Acquired: 7 February, 2003
Price: Donated
Size: 0.2"
Purity: >99%
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Atomized aluminum.
This is a very fine powder of aluminum. It can be used to make thermite (a mixture of iron oxide (rust) and aluminum), which burns very hotly and is used both for welding and for destroying things. It doesn't explode, it just create an extremely intense heat and the product of the reaction is white-hot molten iron.
A friend related the story of being in the signal corps of the army: Every piece of communications equipment that involved cryptographic components came as standard issue with a thermite blanket. In case if imminent enemy capture, the soldiers were instructed to put the thermite blanket over the machine and light it. The burning blanket would then reduce the machine to a puddle of molten slag. In dull moments they entertained themselves by having the blankets melt through the engine blocks of broken down jeeps.
Please note that finely powdered aluminum like this can be explosive under the right conditions. There was a disaster in my town in the summer of 2003, reported by the local newspaper as being an aluminum dust explosion: Here are three articles about it: 1, 2, 3.
Source: United Nuclear
Contributor: United Nuclear
Acquired: 11 April, 2003
Price: $12/8 ounces
Size: 2"
Purity: >99%
Sample Group: Powders
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Aluminum leaf.
Gold leaf you've probably heard of, but it's possible to get very thin sheets of several different pure metals: Click the Sample Group link below to see all the ones I have, which represent pretty much the complete list of those that are commercially available. (Many, many different mixed alloys are also available in leaf form.). Leaf like this is so thin it has to be picked up with special Red Squirrel hair brushes (none of that Gray Squirrel crap, mind you) and when it wafts down onto an object it conforms to the shape of the surface, settling in even to details as fine as a fingerprint.
I bought this leaf from a store in New York when I was visiting there with my six-year-old daughter Addie: You can read about our visit here.
Source: New York Central Art Supply
Contributor: Theodore Gray
Acquired: 11 July, 2003
Price: $5/25 sheets
Size: 3.5"
Purity: >99%
Sample Group: Metal leaf
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Aluminum powder for paint.
I had been having trouble finding aluminum powder in local paint stores, and was starting to wonder if its distribution had been restricted (because it is explosive under certain conditions, see story under previous aluminum powder samples). But it turns out you can still buy it in a well-stocked paint or artists' supply store, as I did with this bottle of very fine aluminum powder. It is intended to be mixed in with other paints or paint bases to make shiny metallic paint.
I bought this powder from a store in New York when I was visiting there with my six-year-old daughter Addie: You can read about our visit here.
Source: New York Central Art Supply
Contributor: Theodore Gray
Acquired: 11 July, 2003
Price: $3
Size: 3"
Purity: >99%
Sample Group: Powders
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Aluminum Penny.
This is an incredibly rare coin: An experimental penny made to see if aluminum would be a good substitute for copper, when the price of copper rose to more than a penny per penny. Only a very small number were every minted, because they decided to go with copper-clad zinc instead. In fact, the coin is so rare that I couldn't possibly actually have one: This is a copy made by a company that specializes in making (legitimate) copies of extremely rare coins. Note that it's clearly stamped "COPY" so there is no confusion.
Source: eBay seller dlrguy
Contributor: Theodore Gray
Acquired: 11 July, 2003
Price: $10
Size: 1/2"
Purity: >99%
Sample Group: Coins
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Link in multi-metal chain.
I had been wondering about how hard it would be to make a multi-part graphite mold with which I could cast chain links around each other. That is, given an existing link, cast a new one interlinked with it. This turns out to be quite do-able: Here is the mold I made (using my drill press as a vertical mill and a round-ended router bit):
 
In case you ever want to try this, I'll give you an important hint: The third link is the real test, not the second one.
Using this mold I have cast a chain out of all the metals I can easily cast. Click the Sample Group link below to see all the links together.
This chain (counted as one sample) is the 600th sample added to my collection.
Source: Hardware Store
Contributor: Theodore Gray
Acquired: 9 August, 2003
Price: $1/pound
Size: 3"
Purity: >90%
Sample Group: Multi-metal Chain
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Hollow cathode lamp.
Lamps like this are available for a very wide range of elements: Click the Sample Group link below to get a list of all the elements I have lamps like this for. They are used as light sources for atomic absorption spectrometers, which detect the presence of elements by seeing whether a sample absorbs the very specific wavelengths of light associated with the electronic transitions of the given element. The lamp uses an electric arc to stimulate the element it contains to emit its characteristic wavelengths of light: The same electronic transitions are responsible for emission and absorption, so the wavelengths are the same.
In theory, each different lamp should produce a different color of light characteristic of its element. Unfortunately, the lamps all use neon as a carrier gas: You generally have to have such a carrier gas present to maintain the electric arc. Neon emits a number of very strong orange-red lines that overwhelm the color of the specific element. In a spectrometer this is no problem because you just use a prism or diffraction grating to separate the light into a spectrum, then block out the neon lines. But it does mean that they all look pretty much the same color to the naked eye.
I've listed the price of all the lamps as $20, but that's really just a rough average: I paid varying amounts at various eBay auctions for these lamps, which list for a lot more from an instrument supplier.
(Truth in photography: These lamps all look alike. I have just duplicated a photo of one of them to use for all of them, because they really do look exactly the same regardless of what element is inside. The ones listed are all ones I actually have in the collection.)
Source: eBay seller heruur
Contributor: Theodore Gray
Acquired: 24 December, 2003
Price: $20
Size: 8"
Purity: 99.9%
Sample Group: Atomic Emission Lamps
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Aluminum-scandium master alloy.
This irregular lump comes from Tim Worstall, the world's leading expert on the scandium trade by virtue of the fact that he is a good fraction of the world's scandium traders. Virtually no pure scandium metal is sold in the world, most of the scandium that trades hands is either scandium oxide, or master alloys like this. A master alloy is a precisely formulated mixture of metals that is meant to be added to a pot of more common metal to form the desired final alloy. This one is aluminum with about 2% scandium added. Why not just buy pure scandium and add it to a pot of aluminum? After all, that would save a lot of weight shipping around 98 pounds of aluminum for every two pounds of scandium. But creating alloys from pure metals is not always so easy. For one thing, the melting point of scandium is much, much higher than that of aluminum: You'd have to heat your aluminum much higher than otherwise necessary in order to get it to absorb the scandium. By purchasing scandium pre-dissolved in aluminum, the end user can simply dump the master alloy chunks into their pot of aluminum near its normal melting point.
Aluminum-scandium alloys are used for things like very expensive bicycle frames, baseball bats, and even a line of light-weight handguns. (Amazingly, two separate readers have written in to me about this last application, both commenting that the guns are very uncomfortable to shoot because the light weight results in a strong kickback.) Tim is excited by the possibilities for expanded use of these alloys, including in things like aircraft wings.
Source: Tim Worstall
Contributor: Tim Worstall
Acquired: 19 January, 2004
Price: Donated
Size: 1.25"
Purity: 98%
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Museum-grade sample.
In early 2004 Max Whitby and I started selling individual element samples identical or similar to the samples we use in the museum displays we build. These are top-quality samples presented in attractive forms appropriate to the particular element. They are for sale from Max's website and also on eBay where you will find an ever-changing selection of samples (click the link to see the current listings).
This ingot shows two kinds of surfaces, one where the metal cooled in contact with a graphite mold, and the top that was in contact with the air. The top surface is particularly interesting in that it shows the degree of contraction when the metal cools (which shows as a depression in the case of aluminum), and sometimes crystal structures that give the surface a wrinkled appearance as in copper or tin.
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 6 March, 2004
Price: See Listing
Size: 4"
Purity: >99%
Sample Group: RGB Samples
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Museum-grade sample.
In early 2004 Max Whitby and I started selling individual element samples identical or similar to the samples we use in the museum displays we build. These are top-quality samples presented in attractive forms appropriate to the particular element. They are for sale from Max's website and also on eBay where you will find an ever-changing selection of samples (click the link to see the current listings).
This ingot is designed to show what the surface of the metal looks like when hammered: By comparing with similar hammered ingots of other metals an idea of the hardness and working characteristics of the metal is given. (We use approximately the same hammering force on each ingot, so lead will show much deeper hammer marks than zinc, for example.)
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 6 March, 2004
Price: See Listing
Size: 4"
Purity: >99%
Sample Group: RGB Samples
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Museum-grade sample.
In early 2004 Max Whitby and I started selling individual element samples identical or similar to the samples we use in the museum displays we build. These are top-quality samples presented in attractive forms appropriate to the particular element. They are for sale from Max's website and also on eBay where you will find an ever-changing selection of samples (click the link to see the current listings).
This sample shows the appearance of the metal when dropped into a bucket of water. The metal is taken to just barely above its melting point, then poured in from close to the water surface, a potentially dangerous operation particularly in the case of aluminum (which can form hydrogen gas that may explode). If the temperature is too high the metal fragments into an almost powder form, so it is a delicate matter to get just the right conditions for the formation of smooth shapes like this.
I chose this sample to represent its element in my Photographic Periodic Table Poster. The sample photograph includes text exactly as it appears in the poster, which you are encouraged to buy a copy of.
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 6 March, 2004
Price: See Listing
Size: 1"
Purity: >99%
Sample Group: RGB Samples
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Museum-grade sample.
In early 2004 Max Whitby and I started selling individual element samples identical or similar to the samples we use in the museum displays we build. These are top-quality samples presented in attractive forms appropriate to the particular element. They are for sale from Max's website and also on eBay where you will find an ever-changing selection of samples (click the link to see the current listings).
This cast ball is designed to show what the surface of the metal looks like when hammered: By comparing with similar hammered balls of other metals an idea of the hardness and working characteristics of the metal is given. (We use approximately the same hammering force on each ball, so lead will show much deeper hammer marks than zinc, for example.)
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 1 May, 2004
Price: See Listing
Size: 2"
Purity: >99%
Sample Group: RGB Samples
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Blobs.
I made these blobs during a photo shoot for one of my Popular Science magazine articles to demonstrate the fact that pure aluminum has a very high surface tensions (resulting in rounded blobs, rather than the runny puddles you get with metals like tin).
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 15 July, 2004
Price: Donated
Size: 2"
Purity: >95%
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Mini element collection.
This is a nice little set from the 1960's. The enclosed price list indicates it cost a few dollars, and the enclosed mercury sample indicates it predates current environmental concerns! Here's a picture of the whole 2-box set:
Source: Blake Ferris
Contributor: Theodore Gray
Acquired: 15 July, 2004
Price: $61/set
Size: 1"
Purity: >98%
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Chain mail.
This is hand-made chain mail, meant to be used in jewelry, and made by Mike Lauter who kindly donated some to my collection, including versions made of four different elements (click the Sample Group link below to see the other variations). If you need some chain mail, he'd probably make some for you.
Source: Mike Lauter
Contributor: Mike Lauter
Acquired: 20 May, 2005
Price: Donated
Size: 2"
Purity: >98%
Sample Group: Chain Mail
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Cigar case.
The fact that this is a genuine Cuban cigar, rare and sought after because it's illegal to import in the US, does not concern us here. What matters is that the case is made of aluminum, a metal whose history parallels the future of Cuban cigars. At one time aluminum too was rare and sought after, so much so that royalty had tableware made of it rather than boring old silver. But then a process was invented to refine it easily, and almost overnight it became cheap and common. Similarly, as soon as a processes is invented to reconcile the insane standoff between the US and Cuba, Cuban cigars will become cheap and common, cashing in their cache until you can buy them at Target for 39 cents, Castro is a distant memory, and the only Cuban Missile Crisis is when one of their pitchers inevitably acquires that nickname.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 25 April, 2006
Price: Donated
Size: 7"
Purity: 95%
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Masterpiece.
In the medieval guild system, an aspiring craftsman first became an apprentice, sweeping the floors and learning at the feat of the master. After some years he (almost always a he) graduated to the status of journeyman, entitled to earn wages and, on his own time, create a piece of his finest work, something good enough to prove to the elders of his guild that he was ready to assume the title of master of his craft. His masterpiece. If there had been a medieval guild of aluminum welders, and if Ethan had lived back then and were even old enough to be a journeyman, this would have been his masterpiece. Unfortunately aluminum had not been discovered and arc welding had not been invented, nor was Ethan born, before the disintegration of the guild system, so this is nothing more than a beautiful, beautiful demonstration of the art and craft of TIG welding. (TIG stands for Tungsten Inert Gas, meaning that a solid tungsten electrode conducts an electric arc to the work piece, heating the work and a stick of aluminum welding rod fed in at the same time.)
Welding aluminum is particularly difficult because aluminum conducts heat extremely well, so as you are trying to weld in one spot, the rest of it is getting hotter and hotter, and if you're not careful, whole sections of it will melt and fall away before you finish the weld. Careful control of the applied heat, and a good feel for the rate at which to move the electrode and feed the rod are necessary to get a good clean bead, such as you see on this cube. Seriously, it's not easy to do this.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 1 July, 2006
Price: Donated
Size: 4"
Purity: 95%
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Naturally occurring nodules.
These nodules of native (naturally occurring) aluminum were found by alert reader Ann Lovgren on the shores of Lake Superior, the largest of the Great Lakes. Now wait a minute, there is no such thing as native aluminum, is there? In fact aluminum is famous for not occurring natively: Despite being the third most abundant element in the earth's crust, accounting for over 8% of the total weight of the crust, it was completely unknown as a metal until 1825 when small, precious samples were first isolated from ore.
But I claim these modules are just as naturally occurring as, say, the white cliffs of Dover. Both are the unintended side effects of life going about its business. The white limestone cliffs that line the English channel around the city of Dover are the remnants of microscopic algae that lived in the ancient seas for countless millions of years. These aluminum nodules are the remnants of aluminum cans, melted down in camp fires over countless dozens of years since the late 1960's when aluminum beverage cans became common.
Just as the cliffs took eons to build to their towering heights, so too will the fields of aluminum nodules slowly grow and spread, washing up on distant beaches millennia after they were formed by the slow but inexorable process of teenagers eliminating the evidence of their lake side beer binges.
Source: Ann Lovgren
Contributor: Ann Lovgren
Acquired: 10 July, 2006
Price: Donated
Size: 1"
Purity: 95%
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Aluminum disk art.
Some time in the early 1990's, for reason that remain obscure to me, I purchased about 1200 pounds of aluminum hard disk platters from a local scrap metal dealer. They came from a local hard disk manufacturer (since gone out of business) and would have gone into 4" computer disk drives, had they not had some kind of flaw that relegated them to the scrap heap.
Years later, my colleague Chris Carlson started coming up with reasons why he'd like to have a stack of them, which of course I quickly agreed to since I still hadn't yet come up with any reasons for keeping them, let alone for buying them in the first place. (Still haven't, by the way.)
Then something quite unexpected happened: For several years in a row on my birthday I started getting these amazing, intricate geometrical constructions made out of, you guessed it, hard disk platters.
They are bent, cut, and riveted with great precision, and in later years started coming with chocolate imprisoned permanently inside. Of course Chris knows how much I love chocolate, which means he either thinks I'm a philistine who would destroy such fine works of art just to get to some chocolate, or he's teasing me. Of course I am a philistine, but even I have my limits, and besides the way these things are built, it's a lot less work to go out and get new chocolate.
They are listed as being acquired in 2006 only because that's when I finally realized that they are obviously good aluminum samples, as well as great works of hard disk art. They actually came into my possession in the late '90s and early '00s.
Source: Chris Carlson
Contributor: Chris Carlson
Acquired: 13 July, 2006
Price: Donated
Size: 5"
Purity: 95%
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Element coin.
Dave Hamric sells element samples under the name Metallium. He's developed a line of coins struck out of various common and uncommon metals: They are quite lovely, and very reasonably priced, considering the difficulty of creating some of them.
Here is the back side of this coin (click either picture to see it larger):
Click the Sample Group link below to see many other coins made of various elements, or click the link to his website above if you want to buy one like this.
Source: Dave Hamric
Contributor: Theodore Gray
Acquired: 1 December, 2006
Price: $4
Size: 0.75"
Purity: >99%
Sample Group: Coins
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Medical Alum.
This antique paper jar of alum was sold for medicinal purposes. Alum (potassium aluminum sulfate) is used in medicine for its drying properties and to stop bleeding.
Source: suesmccoy
Contributor: Theodore Gray
Acquired: 10 March, 2007
Price: $10
Size: 2.5"
Purity: 7.4%
Sample Group: Medical
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Aluminum half cylinders.
The Boeing aircraft company operates a wonderful surplus store in Kent, Washington (near Seattle). I'd read about this place several times, but it was only because I was reminded by Troy McFarland literally days before traveling that I put two and two together: I'm flying to Seattle, and I could go to that surplus store.
It's got everything from old computers to old six ton machine tools, whatever all you might not need anymore for making airplanes. I bought several interesting shapes of aluminum, and some lovely tungsten carbide slot cutting bits from their toolroom section: Click the Source link below to see all the samples that come from this source.
Source: Boeing Surplus Store
Contributor: Theodore Gray
Acquired: 11 August, 2007
Price: $10
Size: 6"
Purity: 95%
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Aluminum shape.
I'm not sure what part of the airplane this is the complement of, but since it came from the Boeing surplus store, it must be a shape you're left over with after you cut out some important piece of airplane structure. Either that or someone was just having fun in the machine room.
Source: Boeing Surplus Store
Contributor: Theodore Gray
Acquired: 11 August, 2007
Price: $15
Size: 12"
Purity: 95%
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Aluminum shape.
It's hard to say what happened here. This thing came from the Boeing surplus store, which means it was meant to be something associated with something Boeing makes, but it didn't work out for some reason. See the next sample for an example where it's obvious why it didn't work out.
Source: Boeing Surplus Store
Contributor: Theodore Gray
Acquired: 11 August, 2007
Price: $15
Size: 6"
Purity: 95%
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Aluminum oops shape.
It's obvious why this chunk of aluminum ended up in the Boeing surplus store. See the bottom right corner? Someone was trying to machine out a nice rounded corner, and they set up the machine to turn the corner too soon: I'm guessing they failed to take into account the diameter of the cutting bit in calculating when the turn should start. The fact that they stopped the machine before it actually finished doing the wrong thing indicates it might have been a manually operated milling machine, which seems surprising considering how common CNC (Computer Numerically Controlled) machining is these days. A CNC machine would have gone ahead and really screwed up big time.
Source: Boeing Surplus Store
Contributor: Theodore Gray
Acquired: 11 August, 2007
Price: $15
Size: 8"
Purity: 95%
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Copper plated aluminum coin.
I got this coin on a trip to Japan last year, and only now got around to photographing and describing it. Japanese one-yen coins are aluminum, but they are undisguised. This one, whose age and value I have no idea of, is copper plated aluminum, presumably an attempt to hide the shame of making your money from such a cheap metal. But the lightness gives it away.
Source: Japan
Contributor: Theodore Gray
Acquired: 20 November, 2007
Price: $1
Size: 0.5"
Purity: >90%
Sample Group: Coins
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Etched cast aluminum bar.
This bar was cast from very high purity aluminum pellets in a mold made by drilling a hole in a graphite slab, then etched with diluted potassium hydroxide. It was cooled slowly to allow crystals inside to grow large, as you can see from the size of the textured patches: Each patch represents a boundary of a single crystal.
Source: Juan Jimenez
Contributor: Juan Jimenez
Acquired: 2 December, 2007
Price: Donated
Size: 2.5"
Purity: 99.9999%
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Rind of sputtering target.
This is the first of several variations of this material I will be posting. Aluminum is widely used for sputtering, a process in which metal is vaporized off a target in a vacuum chamber and deposed in a thin layer on the surface of something else. For example the shiny layer in a CD or DVD disk is sputtered aluminum. To do this you need a sputtering target made of the material you want to deposit.
This very interesting piece of aluminum is scrap from the production of such a target. They started with a cylinder of very pure aluminum and, using tremendous pressure, squashed it down into a pancake about 2" thick and 18" in diameter. Then they sawed off (using a water jet) the outside rim of the pancake to leave a perfect disk. This piece is a slice of the rim that was cut off.
What's most remarkable about it is the strange bumpy ridged surface. I assumed at first it must be formed by some sort of electrodeposition process, as are many bumpy surfaces you'll see typically on raw high-purity metals. But in fact it is formed in a purely mechanical process as the disk is pressed down. There must be internal crystal structures that are sliding and a bumping into each other in way that creates this surface. I will be posting more variations of this material, including a full disk before the rind was cut off, which will show in more detail the strange ridges you see on closer examination.
Source: eBay seller mrj33
Contributor: Theodore Gray
Acquired: 8 December, 2007
Price: $40
Size: 5"
Purity: 99.9996%
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Pressed sputtering target.
Look back a few samples and you'll see a slice of the outer rim of a disk like this. After seeing how beautiful the surface of that slice was, I could not pass up the opportunity to have a full disk of the stuff. Normally these disks would have their irregular outer rim cut off (resulting in samples like he previous rind), but this one ended up slightly under-sized, making it a reject.
Along with the full disk came an explanation from the source of how the disks are made. Basically they start with a tall cylinder and squash it at low temperatures (-50C) and tremendous pressure (1600 tons). The surface texture is a result of large crystal grains in the material sliding against each other.
You can read all about the process in the the patent that covers it.
Source: eBay seller mrj33
Contributor: Theodore Gray
Acquired: 2 February, 2008
Price: Anonymous
Size: 13"
Purity: 99.9996%
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Edge of sputtering target.
See previous sample for an explanation of what you're seeing here. This is the same object as pictured in the previous item description, but this time we're getting a close-up look at the texture of the outer edge. Click the spin video to get a complete tour all the way around the disk (this video has 900 frames compared to the normal 360 frames, as it is such a long way around).
Source: eBay seller mrj33
Contributor: Theodore Gray
Acquired: 2 February, 2008
Price: Anonymous
Size: 13"
Purity: 99.9996%
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Aquamarine Beryl. (External Sample)
The metal beryllium is named after this mineral. I used to say here that beryl was named after beryllium, but reader Jeffrey Shallit kindly pointed out the absurdity of that notion, since the mineral was known and named long before the metal. He writes:The word beryl comes from ancient Greek and according to the OED, first appeared in English in 1305. But beryllium was not discovered until 1797 and the word "beryllium" did not appear in English until 1863. Beryllium the metal is fairly plain looking and toxic, while beryl the mineral is quite beautiful and comes in a great variety of shapes and colors.
Location: John Gray's Collection
Photographed: 11 March, 2003
Size: 3"
Composition: Be3Al2Si6O18
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